The solar water heaters of the prior art mainly include the pressure-bearing type and the non-pressure-bearing type.
The operating principle of the pressure-bearing type of solar water heaters is that: tap water flows into the water tank and the heat pipe through a control switch, the heat collecting tube absorbs solar radiation and then transmits thermal energy to the cold water in the heat pipe, so as to circularly heat the water in the water tank, however, as the water tank is an enclosed construction as a whole, during usage it is necessary to open the cold water inlet and utilize the water pressure of the tap water to push out the hot water of the water tank, so as to allow hot water to flow into the water using unit through the water outlet. The water tank of this structure type bears pressure from tap water, has relatively larger water outflow rate and better usage comfort level, however, the water tank of this structure type is required to bear water pressure of up to 7 MPa, in addition, a heat pipe structure needs to be further provided inside the tank, and there are also requirements for relatively high sealing effect, and relatively thicker material, thus causes relatively higher cost of the solar water heater.
The operating principle of the non-pressure-bearing type of solar water heaters is that: tap water flows into the water inflow and outflow port (water baffle board) of the water tank, until the water tank and the glass heat pipe are filled, the glass heat pipe absorbs sunlight and then heat the water in the water tank and the glass heat pipe, and after being heated, the water of the water tank flows to the indoor water using unit through the water inflow and outflow port for the users to use. The water tank and the glass heat pipe of this structure type only bear water pressure generated corresponding to the height of the water tank, which is relatively small pressure, therefore, the glass heat pipe and the water tank are not required to have pressure-proof designs, thus save material and reduce cost relative to the pressure-bearing type of solar water heater. However, because the mounting height of the water tank is limited by the architectural structure, it is generally difficult for the solar water heater of this type of structure to provide relatively higher water pressure to the water outflow unit, which results in relatively smaller water outflow rate of the water outflow unit and negatively affects the usage comfort level.
Chinese patent literature under CN103016421A disclosed a jet device and a water heater valve having the jet device, which belongs to the non-pressure-bearing type of water heater valve, wherein, the effects of jetting pressurizing and reducing cost are simultaneously achieved through reasonable configuration of the jetting pressurizing structure. However, for the water heater valve disclosed in this patent literature, the opening diameter of its nozzle is constant, and when adjusting inflow rates of cold water and hot water respectively through the cold water flow rate regulating switch and the hot water flow rate regulating switch, if the opening size of the cold water flow rate regulating switch is adjusted to be smaller than the opening size of the nozzle, then the pressure of the working fluid inside the nozzle will be reduced, so as to reduce the jet velocity of the working fluid of cold water, thereby causing weaker effect of hot water pumping, which leads to lower usage comfort level when used in summer.
Chinese patent literature under CN102086941B disclosed a water mixing valve, comprising a valve body, wherein, a valve cold water inlet, a valve hot water inlet, a valve water outlet, and a nozzle connected to the valve cold water inlet are provided on the valve body, a nozzle cold water inlet and a nozzle cold water outlet are provided on the nozzle, a hot water adjusting cavity communicated with the valve hot water inlet and a water mixing cavity communicated with the valve water outlet are also provided inside the valve body, the water mixing cavity and the hot water adjusting cavity are interconnected through a valve hot water outlet positioned at one end of the hot water adjusting cavity, and the water mixing cavity is also communicated with the nozzle through the nozzle cold water outlet. When flow rate of hot water needs to be adjusted, the nozzle can be screwed into or out of the valve body, so as to increase or decrease the cross-sectional area of the inlet of hot water, and at the same time, the cross-sectional area of the inlet of cold water is also increased or decreased, as a result, the mixing proportion of cold water and hot water is adjusted. However, it has the following defects during usage:
When the nozzle is rotated, the needle valve moves with the nozzle, and during this process, there is no relative motion occurred between the nozzle and the needle valve, so that the cross-sectional area of the outlet of cold water is always kept constant, as a result, when the cross-sectional area of the inlet of cold water is smaller than the cross-sectional area of the outlet of cold water, the water pressure of cold water inside the nozzle will be very low, and it will be difficult to achieve better jetting effect, and that, in order to ensure better jetting effect, the needle valve needs to be adjusted at the same time, so as to decrease the cross-sectional area of the outlet of cold water, which requires simultaneous adjustment of the needle valve and the nozzle with increased difficulty of usage, and if the needle valve and the nozzle are not adjusted at the same time, then it is difficult to ensure better water out flowing effect and higher usage comfort level.
It can be understood from the preceding discussion that, how to improve the water mixing valve in order to simultaneously achieve higher usage comfort level, lower usage cost and more convenient operation is a technical problem that is unsolved in the prior art.